new helper: mount_subtree()

[pandora-kernel.git] / fs / btrfs / super.c

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 57080df..17ee7fc 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -197,7 +197,7 @@ static match_table_t tokens = {
        {Opt_subvolrootid, "subvolrootid=%d"},
        {Opt_defrag, "autodefrag"},
        {Opt_inode_cache, "inode_cache"},
-       {Opt_no_space_cache, "no_space_cache"},
+       {Opt_no_space_cache, "nospace_cache"},
        {Opt_recovery, "recovery"},
        {Opt_err, NULL},
 };
@@ -448,6 +448,7 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags,
                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_subvol:
+                       kfree(*subvol_name);
                        *subvol_name = match_strdup(&args[0]);
                        break;
                case Opt_subvolid:
@@ -710,7 +711,7 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
        if (btrfs_test_opt(root, SPACE_CACHE))
                seq_puts(seq, ",space_cache");
        else
-               seq_puts(seq, ",no_space_cache");
+               seq_puts(seq, ",nospace_cache");
        if (btrfs_test_opt(root, CLEAR_CACHE))
                seq_puts(seq, ",clear_cache");
        if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
@@ -824,13 +825,9 @@ static char *setup_root_args(char *args)
 static struct dentry *mount_subvol(const char *subvol_name, int flags,
                                   const char *device_name, char *data)
 {
-       struct super_block *s;
        struct dentry *root;
        struct vfsmount *mnt;
-       struct mnt_namespace *ns_private;
        char *newargs;
-       struct path path;
-       int error;
 
        newargs = setup_root_args(data);
        if (!newargs)
@@ -841,39 +838,17 @@ static struct dentry *mount_subvol(const char *subvol_name, int flags,
        if (IS_ERR(mnt))
                return ERR_CAST(mnt);
 
-       ns_private = create_mnt_ns(mnt);
-       if (IS_ERR(ns_private)) {
-               mntput(mnt);
-               return ERR_CAST(ns_private);
-       }
-
-       /*
-        * This will trigger the automount of the subvol so we can just
-        * drop the mnt we have here and return the dentry that we
-        * found.
-        */
-       error = vfs_path_lookup(mnt->mnt_root, mnt, subvol_name,
-                               LOOKUP_FOLLOW, &path);
-       put_mnt_ns(ns_private);
-       if (error)
-               return ERR_PTR(error);
+       root = mount_subtree(mnt, subvol_name);
 
-       if (!is_subvolume_inode(path.dentry->d_inode)) {
-               path_put(&path);
-               mntput(mnt);
-               error = -EINVAL;
+       if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
+               struct super_block *s = root->d_sb;
+               dput(root);
+               root = ERR_PTR(-EINVAL);
+               deactivate_locked_super(s);
                printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
                                subvol_name);
-               return ERR_PTR(-EINVAL);
        }
 
-       /* Get a ref to the sb and the dentry we found and return it */
-       s = path.mnt->mnt_sb;
-       atomic_inc(&s->s_active);
-       root = dget(path.dentry);
-       path_put(&path);
-       down_write(&s->s_umount);
-
        return root;
 }
 
@@ -890,7 +865,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
        struct super_block *s;
        struct dentry *root;
        struct btrfs_fs_devices *fs_devices = NULL;
-       struct btrfs_root *tree_root = NULL;
        struct btrfs_fs_info *fs_info = NULL;
        fmode_t mode = FMODE_READ;
        char *subvol_name = NULL;
@@ -904,8 +878,10 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
        error = btrfs_parse_early_options(data, mode, fs_type,
                                          &subvol_name, &subvol_objectid,
                                          &subvol_rootid, &fs_devices);
-       if (error)
+       if (error) {
+               kfree(subvol_name);
                return ERR_PTR(error);
+       }
 
        if (subvol_name) {
                root = mount_subvol(subvol_name, flags, device_name, data);
@@ -917,15 +893,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
        if (error)
                return ERR_PTR(error);
 
-       error = btrfs_open_devices(fs_devices, mode, fs_type);
-       if (error)
-               return ERR_PTR(error);
-
-       if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
-               error = -EACCES;
-               goto error_close_devices;
-       }
-
        /*
         * Setup a dummy root and fs_info for test/set super.  This is because
         * we don't actually fill this stuff out until open_ctree, but we need
@@ -933,24 +900,36 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
         * then open_ctree will properly initialize everything later.
         */
        fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
-       tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
-       if (!fs_info || !tree_root) {
+       if (!fs_info)
+               return ERR_PTR(-ENOMEM);
+
+       fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+       if (!fs_info->tree_root) {
                error = -ENOMEM;
-               goto error_close_devices;
+               goto error_fs_info;
        }
-       fs_info->tree_root = tree_root;
+       fs_info->tree_root->fs_info = fs_info;
        fs_info->fs_devices = fs_devices;
-       tree_root->fs_info = fs_info;
 
        fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
        fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
        if (!fs_info->super_copy || !fs_info->super_for_commit) {
                error = -ENOMEM;
+               goto error_fs_info;
+       }
+
+       error = btrfs_open_devices(fs_devices, mode, fs_type);
+       if (error)
+               goto error_fs_info;
+
+       if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
+               error = -EACCES;
                goto error_close_devices;
        }
 
        bdev = fs_devices->latest_bdev;
-       s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
+       s = sget(fs_type, btrfs_test_super, btrfs_set_super,
+                fs_info->tree_root);
        if (IS_ERR(s)) {
                error = PTR_ERR(s);
                goto error_close_devices;
@@ -959,12 +938,12 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
        if (s->s_root) {
                if ((flags ^ s->s_flags) & MS_RDONLY) {
                        deactivate_locked_super(s);
-                       return ERR_PTR(-EBUSY);
+                       error = -EBUSY;
+                       goto error_close_devices;
                }
 
                btrfs_close_devices(fs_devices);
                free_fs_info(fs_info);
-               kfree(tree_root);
        } else {
                char b[BDEVNAME_SIZE];
 
@@ -991,8 +970,8 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 
 error_close_devices:
        btrfs_close_devices(fs_devices);
+error_fs_info:
        free_fs_info(fs_info);
-       kfree(tree_root);
        return ERR_PTR(error);
 }